Device and method for measuring coagulation time and platelet activity

ABSTRACT

The present invention refers to a novel device for measuring coagulation time and platelet activity wherein the patient can measure his or her coagulation time and platelet activity without the aid of medical professionals due to the fact that this device is fully autonomous. A blood sample ( 14 ) is deposited in the dish ( 3 ) and reacted with a reactant ( 16 ). The display ( 9 ) then shows the coagulation time and platelet activity of the patient.

OBJECT OF THE INVENTION

The present invention refers to a novel device for measuring coagulationtime and platelet activity and to a process thereof, whereby, thanks tothis electromechanically-operated, small-sized and battery-powereddevice, a patient can measure his or her coagulation time and plateletactivity without the aid of medical professionals, furthermore beingable to be connected to the medical center responsible for the patientclinical follow-up by means of telephone, Internet network or any othercommunication means.

BACKGROUND OF THE INVENTION

The traditional method regarding measuring coagulation time and plateletactivity of a patient hitherto has consisted of the analysis of theseparameters in a clinical laboratory, by means of using instrumentssituated in clinical analysis laboratories, which implies frequent tripsfor patients, with the resulting social and financial damage for them,as well as for public health institutions, in addition to usually notbeing carried out with the periodicity recommended by medicalspecialists.

All the drawbacks mentioned above are emphasized when the measurement ofcoagulation time and platelet activity is carried out on a patient withcardiovascular diseases, given that these patients are treated withanticoagulant products with personalized doses for each patient.

These doses depend to a large extent on the blood characteristics ofeach patient, the two most important ones being those characterized bythe parameters called “coagulation time” and “platelet activity”,therefore they must periodically come to a clinical analysis laboratoryto carry out the corresponding analyses in order to measure saidparameters.

DESCRIPTION OF THE INVENTION

With the device for measuring coagulation time and platelet activity andprocess thereof, object of the present invention, all the drawbacksmentioned above are intended to be palliated or improved to which end itis a measuring process by means of using a device in which a blood dropof the patient is introduced, such that this blood falls in the device,reacting with a reactant which is incorporated in the device whereby achange of the blood state is achieved and, thanks to this change, thecoagulation time and platelet activity can be measured. To that end, itis a device that includes a frustoconical-shaped cup inside of which alikewise frustoconical-shaped rotor rotates, with the same taper but ofa slightly smaller diameter. The blood with the reactant is placed inthe gaps between the rotor and the cup, the reactant serving as thecoagulation precursor whereby a clot is formed in the gap, causing adecrease of the rotating speed of the rotor. This speed decrease ismeasured by a speed sensor and interpreted by an electronic circuit,resulting in the measurement of the coagulation time and/or plateletactivity.

The operation of this device is prepared by using batteries, whichprovides this device with an obvious autonomy.

DESCRIPTION OF THE DRAWINGS

To complement the description being made and for the purpose of helpingto better understand the features of the invention, a series of drawingsis attached to the present specification as an integral part thereof, inwhich with an illustrative and non-limiting character, the following hasbeen shown:

FIG. 1 shows a schematic view of the process for obtaining themeasurement of the “coagulation time” and “platelet activity”parameters.

FIG. 2 shows a view of mechanical operating of the invention.

FIG. 3 shows a view of the interconnection of the components.

PREFERRED EMBODIMENT OF THE INVENTION

As can be seen in the figures, a blood sample (14) placed in the dish(3), which is connected with the diametrical conduit (4), which has thereactant (16), is distinguished in the first place. This blood sample(14) together with the reactant (16) is ejected to the gap generatedbetween the cup (1) and the rotor (2), thanks to the aid of thecentrifugal force generated 25 by the circular motion of the rotor (2)rotating due to the action of the electric motor (8), a speed sensor (7)is used for measuring the speed decrease of the rotor (2) caused by clot(15) resulting from the mixing of the blood sample (14) and reactant(16);. Heating element (6) is used for maintaining the assembly at atemperature between 35 and 40 degrees centigrade and its correspondingtemperature sensor (5) is used for assuring this temperature range iskept.

In one of the prepared embodiments, measuring device (13) is implementedwith a small frustoconical or cylindrical-shaped cup (1), inside ofwhich a likewise frustoconical-shaped rotor (2) coaxially rotates. Rotor(2) has the same taper and slightly smaller diameter, such that there isa small clearance between them and there is no friction between theirrespective side walls nor between their bases.

Blood sample (14) of a patient and reactant (16) functioning as acoagulation activator, are placed in the gaps between interior rotor (2)and cup (1). The reactant (16) to be used will depend on whether the“coagulation dire” or “platelet activity” is to be measured.

Due to the rotation of the rotor (2), both products are thoroughlymixed, a biochemical process which, after a certain time, gives rise todie clot (15) formation being initiated, causing an increase ofmechanical friction between the rotor (2) and the cup (1) detected dueto its effect on the speed and on the torque of the cylinder.

In the event that the coagulation time is being measured, friction willsuddenly increase in the moment in which clot (15) is produced. The timeelapsed between the start of the process and the moment in which thefriction increase occurs is measured by a control circuit (11), and withthe due corrections automatically carried out, the so called“coagulation time” is obtained.

If “platelet activity” is being measured, the friction increase will beprogressive in accordance with clot (15) formation and the manner inwhich it varies will be analyzed by the control circuit (11) to measuresaid parameter.

Given that the entire process must be carried out in a temperature rangeof 35 to 40° C., a heating element (6) and a temperature sensor (5) areincorporated under the cup (1). The control circuit (11) is in charge ofmaintaining the cup (1) and the rotor (2) at said temperature and ofnotifying the patient by the display (9) that the measuring device (13)is ready to be used once said temperature is reached and stabilized.

For the purpose of facilitating the dosage of the reactant (16) and ofthe patient blood sample (14), the rotor (2) has a diametrical conduit(4) in which the reactant (16) is housed.

For the purpose of facilitating the placing and subsequent dosage of thepatient blood sample (14), the rotor (2) has a small dish (3) in thecenter of the upper face, which is connected at its lower portion withthe center of the diametrical conduit (4) containing the reactant (16).

Once the measuring device (13) is on, and the time necessary to reachthe operating temperature has elapsed, which is indicated to the patientby means of a small display (9), the patient will place a blood sample(14), obtained by a finger puncture, for examples in dish (3) intendedfor that purpose. The patient will then indicate to the measuring device(13) by means of the keyboard (10) that the measuring process can begin.

Said process begins with the phase of ejecting the reactant (16) and theblood sample (14) required for the clot (15) formation to occur. Forthat purpose, the rotor (2) is subjected to a very high rotating speedby means of an electric motor (8), the rotating shaft of which issolidly attached thereto, whereby, due to the centrifugal force, thereactant (16) will be ejected to the gap existing between the rotor andthe cup.

Due to the vacuum generated in the diametrical conduit (4) of the rotor(2) due to the ejection of the reactant (16) contained therein, theblood sample (14), previously placed in the dish (3) located in theupper portion of the rotor (2), is also ejected towards said gap where,aided by the rotating motion, it is mixed with the reactant (16), thecoagulation process itself beginning in that moment.

The amount of the ejected blood sample (14) will depend on the rotatingspeed of the rotor (2) and on the time the latter is rotating at highspeed. Both parameters are controlled by the control circuit (11).

Once the reactant (16) and the blood sample (14) are ejected, the rotor(2) begins to rotate at a very slow speed. In this phase of the process,the control circuit (11) is in charge of measuring and controlling thespeed and torque of the motor solidly attached to the rotor (2) by meansof the speed sensor (7). The increases in the braking torque ordecreases of the speed will indicate that coagulation is taking place. Acalculation, carried out by the control circuit (11) from saidvariations according to the time, will serve for measuring the parameterobject of the analysis.

The control circuit (11) is configured as a device provided with theelectronic and electric components necessary for providing the necessaryenergy to the heating element (6) once the user activates the cyclestart order by means of the keyboard (10), until the temperature sensor(5) indicates to the user that the suitable temperature has beenreached, at which time the patient will be notified by means of thedisplay (9) that he or she can place the blood sample (14) in the dish(3).

The control circuit (11) is configured as a device provided with theelectronic and electric components and automatisms necessary forproviding the necessary power to the electric motor (8) by means of thepower supply unit (12) once the patient has placed the blood sample (14)in the dish (3), such that the rotor (2) rotates at the required speedand for the necessary time to eject the reactant (16) contained in thediametrical conduit (4) of the rotor (2) due to the effect ofcentrifugal force, as well as the blood sample (14) placed in the dish(3), due to the effect of the vacuum generated due to the ejection ofthe reactant and likewise to the centrifugal force. circuit (11)includes the electronic and electric components for providing thenecessary power to the electric motor (8) by means of power supply unit(12) so that the motor rotates at a certain speed once the ejectioncycle of the reactant (16) contained in the diametrical conduit (4), andof the blood sample (14) previously placed in the dish (3), hasconcluded.

Control circuit (11) is configured as a device provided with thenecessary electronic and electric components for measuring at all timesthe rotating speed during the rotating phase of rotor (2), from speedsensor element (7) connected thereto, as well as the braking torqueexerted by the clot (15) formation located in the gap existing betweenThe rotor (2) and the cup (1) by measuring the current consumption ofthe motor (8).

The control circuit (11) is configured as a device provided with thenecessary electronic and electric components to carry out the necessarycalculations from the rotating speed and braking torque values obtainedaccording to what is indicated in the previous paragraph, designed forobtaining the parameters called “coagulation time” or “plateletactivity” as appropriate.

Having sufficiently described the nature of the present invention, aswell as a manner of taking it to practice, all that remains is to addthat it is possible to introduce changes in shape, materials andarrangement in the invention as a whole and in parts making it up, aslong as said changes do not substantially change the features of theinvention which are claimed below:

1. A device for measuring the coagulation time and platelet activity ina blood sample, comprising: A) electric motor means for providing arotational movement, said motor means further including means forsensing and controlling the speed of said rotational movement, which isproportional to the current drawn from an electric power source; B)rotor means having a substantially frustoconical shape, said rotor meansbeing coupled to said motor means for receiving said rotationalmovement; C) a stationary frustoconical cup member coaxially housingsaid rotor means so that a surface gap is defined between said rotormeans and said cup member; D) container means disposed within the rotormeans for receiving a predetermined amount of a blood sample andcoagulation reactant, wherein said container means includes conduitmeans with at least one transversal outlet cooperatively disposed todeposit a predetermined amount of said blood sample and reactant in saidgap; E) control circuit means for measuring the changes of saidrotational movement over predetermined periods of time to determinefrictional forces related to the clotting of said sample of blood andreactant in said gap; and F) means for controlling and keeping thetemperature of said device over a predetermined range.
 2. The device setforth in claim 1 further including: G) means for measuring the currentdrawn by said motor means and being connected to said control circuitmeans so that said current drawn is sensed over predetermined periods oftime that are correlated with the platelet activity of said bloodsample.
 3. The device set forth in claim 2 wherein said motor meansincludes a rotating shaft and said cup member includes a cooperativethrough opening that permits said shaft to go through.
 4. The device setforth in claim 3 wherein said conduit means holds said coagulationreactant.
 5. The device set forth in claim 4 wherein said means forcontrolling and keeping the temperature of said device keeps thetemperature between 35° C. and 40° C.
 6. The device set forth in claim 5wherein said blood sample and coagulation reactant are deposited in saidgap with the aid of centrifugal forces.